1. Field of the Invention
The disclosure relates to dye sensitized solar cells, and in particular relates to photo curable glues applied in the dye sensitized solar cells.
2. Description of the Related Art
Dye sensitized solar cells (DSSC) have advantages such as low cost, wide absorption band, and simple processes. Although the DSSC disclosed in Nature 353, 737-740 published by Grätzel on 1991, Oct., 24 can be commercialized, many problems therewith still exist. Not only does the dye and electrolyte play an important role for the cell, the sealing glue also plays an important role. For example, commercially sealed cells should pass durability tests, such as high temperature or light exposure tests.
Generally, mainstream sealing materials for the DSSC are the thermoplastic material Surlyn or Bynel, which are usually thermally pressed and paired assembled by heating. The heating mechanism appeals to be simple, however, it has the following disadvantages. (1) The heating temperature is often between 130° C. to 170° C., which may influence the quality of the dye adsorbed on the titanium oxide working electrode. The heating process will cause desorption or deterioration of the dye, thereby reducing the DSSC efficiency. (2) The thermoplastic material is limited by its physical properties such as Tg, and cannot be retained under a high moisture and high temperature environment. In other words, the DSSC utilizing the thermoplastic sealing glue easily decays under a high moisture and high temperature environment, thereby influencing its commercialization. (3) A space between the working electrode and the opposite electrode is not easily controlled by thermally pressing glue. As such, the space should be controlled by the supply, such that process flexibility is reduced.
UV curable sealing glue having advantages such as simple operation, designable material, simple processes, high thermal stability, and high chemical stability, is widely applied in several industries. However, commercially available UV glues have not been developed for DSSC usage. One aspect is that the DSSC industry is new, and it is only now being studied by academic and glue suppliers. Another aspect is that the sealing glue for the DSSC has to be able to withstand corrosion of the electrolyte with high activity, resist sunlight exposure, and sustain vapor pressure from thermal expansion and contraction of the electrolyte having a high boiling point. In short, the frame glue of the DSSC should meet strict requirements.
Accordingly, a specifically designed UV glue composition for a DSSC is called-for.